The 2K Games Forums have a list of the changes in a new patch for XCOM: Enemy Unknown that's now available to update the newly released installment in the counter-UFO strategy series (thanks Scott). Here's word on what this does:

We wanted to let you know the details for the PC update for XCOM: Enemy Unknown that went live today (10/11/12). I've included the notes on this patch below:

Various visibility/hiding optimizations

Multiplayer text chat support (press J to activate)

Mouse button 4/5 will switch soldiers in the Barracks

ESC hides the movement grid, if you do not want to commit to a move while it is activated

Squad Sight ability optimization

Fixed issue when equipping two grenades with Deep Pockets.

Fixed Rapid Fire sometimes consuming too much ammo.

SHIVs that are damaged will no longer become unusable.

Fixed some hangs/soft crashes in tactical combat.

Replaced software cursor with the operating system cursor to reduce lag and framerate dependence.

Fixed rendering bug which causes some soldierís hair to appear as if it is rendering on top of environment fog.

Prez wrote on Oct 11, 2012, 21:47:On the Firaxis forum someone (who may be a developer or just someone talking out their ass) said the patch's size is a function of the way the code is compiled - if you change one line the entire file needs to be downloaded.

I guess it's possible, but I know fuck-all about such things.

That's absolutely possible. It also shows that they compiled it in the worst fucking way imaginable. Fucking awesome. So everything they have a patch, we'll have to download 2 GBs or more? Yay.

Thanks Firaxis!

Creston

Didn't the same thing happen with The Witcher 2 when it came out? I seem to remember something like a 15gb patch, or something ridiculous, that I had to download to play it after an update.